This invention relates to a method of polymerizing vinyl chloride and vinylidene chloride. In particular, it relates to the use of supercritical, subcritical, or liquid carbon dioxide as a solvent in which vinyl chloride or vinylidene chloride is polymerized.
Polyvinylchloride (PVC) is made by polymerizing vinyl chloride monomer (VCM) in an aqueous suspension, an aqueous dispersion, or bulk (i.e., without a solvent). While these processes are effective, there are some problems associated with them. For example, in the suspension and dispersion processes energy is needed to evaporate solvent. In all three processes, unreacted VCM must be removed from the PVC because it is a carcinogen, and its removal to acceptable levels is difficult. Also, those processes are subject to reactor fouling and the formation of fish eyes in the PVC.